Art of refrigeration



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Patented June 30, 1936 ART F REFRIGERATION Walter Gordon Clark, Los Angeles, Calif., assigner to Air Ice Research & Development Corp., Los Angeles, Calif., a corporation of Delaware Application June 18, 1932, Serial No. 617,936

15 Claims. (Cl. 6.2-121) This invention relates to certain improvements in the art of refrigeration, particularly improvements in methods and apparatus for manufacturing solidified refrigerants from liquefiable gases such as carbon dioxide. It is to be understood, however, that the inventions herein described are not limited in their application to the manufacture of solidied refrigerants of the type represented by solidified carbon dioxide, as such inventions may be readily adapted lto the manufacture of other types of solidified refrigerants such as, for example, water ice.

For the purpose of facilitating the understanding of the inventions, reference will hereinafter be made most specically to the application of the inventions to the art of manufacturing solidiled refrigerants from a liquefied gas such as carbon dioxide. In the manufacture of solidified carbon dioxide for refrigerating purposes, diiii- 20 culty has been encountered in producing blocks or bodies of the refrigerant. Because of the extremely low temperature of the material, there is a tendency for the material to adhere to metallic surfaces. Some attempt has been made to solid- 25 ify the gas in the form of snow and then compress the snow into blocks or cubes. Obviously,

a large amount of equipment is required. This invention, on the other hand, discloses an apparatus whereby the liquefied gas may be solidied 30 directly into a block of any desired form,.thereby obviating the necessity of compressing a pulverulent or finely divided material.

The invention also relates to improved meth- Y ods whereby the introduction of the liqueed gas into a molding container may loe regulated.

Moreover, the invention contemplates the regulation and control of the block-forming step by temperature variations of the containers in which such blocks are formed.

In general, the method of this invention contemplates the admission of a refrigerant in liquid formv into a metallic container, the solidication of the refrigerant within'the container, the'control of introduction of liquid refrigerant into the container in accordance with temperature variations of said container, and the control of the ejection of the solidified refrigerant from the container by further temperature variations in the metallic container. An apparatus suitable for carrying out this method and preferred forms 'which the container may assume, are disclosed hereinafter.

In describing certain specific embodiments of this invention, reference will be had to the 'appended drawing, in which Fig.y 1 is a longitudinal section of an apparatus wherein the method of this invention may be placed in operation.

Fig. 2 is an enlarged longitudinal section of a portion of the device shown in Fig. 1.

Fig. 3 is a perspective view of a body of refrigerant of a desired and suitable form made in the apparatus shown in Figs. 1 and 2.

Fig. 4 diagrammatically illustrates automatic means responsive to variations in temperature of the container for controlling the operation of the device.

As illustrated by the apparatus shown in Fig. 1, the container I may consist of an outer cylindrical section 2 and an axially disposed concentric inner cylindrical section 3 of materially smaller diameter. The inner and outer cylindrical sections 2 and 3 may then be connected at one end by an annular metallic disk 4. The front end of the inner cylindrical member 3 may be closed as by means of a metallic member 5. As a result, the metallic container I is in the form of an annular cylinder capable of receiving a substance in the space between the inner and outer concentric cylindricalmembers 2 and 3.

The container I is preferably positioned in a heat-insulated housing 6 which, as shown, may consist of a metallic housing 1 and an exterior layer 8 of heat-insulating material. The interior surfaces of the housing 6 are provided with a layer of electrical insulation 9 such as a layer of impregnated paper, parchment, phenol condensation product, or the like. The housing 6 is spaced from the container I, cooling coils being placed between the housing and. the container. An inlet line I0 provided with a suitable pressurereducing or other valve II passes through the housing 6 and communicates with a coil I2 encircling the container I.

When the inlet line l0 connects one end of said coil, the opposite end of the coil I2, indicated at I3, is connected to a coil of relatively small diameter, indicated at I4, positioned within the cylindrical member 3 of the container I. The discharge end of the coil I4, indicated at I5, communicates with an outlet line I6 which is axially positioned within the inner member 3 of the container I. This discharge line I6 may lead to a desired point of a gas purification and liquecation system. For example, if the non-condensible gases of a carbon dioxide system are used for refrigerating purposes in the coils I2 and I4, the discharge line I6 may lead back to the final condensation of the carbon dioxide liquefying system or to some point prior therein.

Means are provided whereby electrical connectio-n between the container I and the coils I2 and I4 is prevented. Such means may include a. coa-ting of electrical insulation indicated at 25, on the exterior surfaces of the container I, such coating 25 extending to the internal surfaces of the centrally located cylindrical member 3 as indicated at 26.

The lower end of the housing 6, and particularly the metallic member 1 thereof, may be provided with an outwardly extending flange I1 exteriorly threaded as shown and adapted to receive a circular closure member or door I8 provided with a fiange I9 adapted to engage with the threaded flange I1 of the housing. The door I8 is connected by means of a yoke 20 with a lever arm 2I, a rotatable connection being used between the door I8 and the lever 2I as by means of a pin 22. lIhe lever 2| is preferably rprovided with a counterweight 23, sai-d lever being pivoted as indicated at 24 from any stable and stationary support.

The container I is provided with means for admitting a solidifiable refrigerant thereinto. For example, a container 30 is supplied with liquefied carbon dioxide through an inlet line 3I leading from a suitable gas separating and purifying system. The liquefied gas from the container 30 is then admitted into the container I at some point removed from the closure member I8 which cooperates with said container. An inlet line of such character is indicated at 32 and is provided with a suitable valve 33. `This inlet line 32 is shown communicating with the top of the container I, the discharge opening closed by the closure I8 being at the bottom of said container. The top of the container I is also provided with a discharge line 34 whereby unsolidiiied refrigerant or vaporized refrigerant from the container I may be returned to the gas purifying and liquefying system which may be at an appreciable superatmospheric pressure. A gas purifying and liquefying system is shown in co-pending application Serial No. 573,365.

Means are provided whereby electrical contact may be made with the inner and outer cylindrical members 2 and 3 of the container I. As shown, an electrical contact may be made to the inner cylindrical member 3 by means of a contact member 35 carried by the closure I 8, said contact member 35 being adapted to make an electrical connection with the member 5 joining or extending across the end of the cylindrical member 3. The contact member 35 is electrically insulated from the closure member I8 as by means of a suitable electrical insulating bushing 36.

The inner face of the closure member I8 may also be provided with a plurality of electrical contacts such as are indicated at 31. These contacts may convey electrical energy to a ring A38 adapted to contact with the outer cylindrical member 2 of the container I. This ring, as well as the contact elements 31, are electrically insulated from the closure I8 as by means of composition bushings 39.

As shown diagrammatically in Fig. l, the contact members 35 and 31 are supplied with electrical energy by lines 4D and 4I respectively, said lines being provided with a switch 42. Opposite ends of either the external cylindrical member 2 or the inner cylindrical member 3 are then connected with a Wheatstone bridge or other suitable instrument capable of measuring changes in resistance of such members. As

shown in Fig. l, the opposite ends of cylindrical member 2 are connected as by leads 43 and 44 with a Wheatstone bridge circuit which includes a galvanometer 45, a variable resistance 48 and a source of current such as a battery 41.

The operation of the apparatus described hereinabove is as follows:

The container I is closed by the closure member I8, the switch 42 being open. Liquefied refrigerant is then admitted into the container I as, for example, by opening the valve 33. The pressure of said liquefied refrigerant is reduced and the reduction in pressure coupled with the refrigerating effect of the expanding gases in the coils I2 and I4 causes the refrigerant to solidify within the container I. As the level of solidified refrigerant rises in the container I, the walls of the container drop in temperature. The drop in temperature of such container walls is utilized in indicating the approximate height of the solidified refrigerant in the container, inasmuch as the electrical conductivity or drop in electrical resistance of the outer container I is measured or observed during the admission of the refrigerant into the container and during the forma-tion of the solid body therein by the Wheatstone bridge arrangement connected to opposite ends of the outside cylinder member 2 of the container I. After a few preliminary trials, the operator will be able to correlate the galvanometer readings with the height of the solidified refrigerant within the container I, inasmuch as the electrical conductivity or resistance of the metallic container will vary with decrease in temperature caused by solidiflcation of the refrigerant within said container. After the container has been lled with solidified refrigerant, the admission of further refrigerant by line 32 is discontinued and the resulting blockV or annular cylinder of solidied refrigerant is then discharged from the container I. Although the gases passing through coil I2 are at a very low temperature at all times and exert Va chilling effect on the walls of the container, the temperature of these walls is entirely dependent upon the rate at which heat is being dissipated or absorbed by such walls and whether the interior of the container is exposed to the atmosphere or liquid carbon dioxide. Ordinarily, equilibrium conditions (as far as heat transfer is concerned) do not obtain, the time element playing an important part in producing Vequilibrium conditions.

Ordinarily, it would be rather difiicult to .discharge the solidified refrigerant from the container in which it was frozen because of the adherence of the refrigerant to the metallic container. In accordance with this invention, however, switch 42 is closed and an electrical current passed through contacts 31 and 35 and thereby through the inner and outer cylindrical members 2 and 3 of the container I. This flow of current is sufcient to slightly increase the temperature of the container, suchV increase in temperature being caused by the fiow of electrical current therethrough. An increase in the temperature of the container causes the solidified refrigerant immediately in contact with the container surfaces to liquefy and/or gasify (depending upon the type of material used), thereby breaking the bond between the solidified block and the metallic container. A certain amount of pressure is thus developed within the container, said pressure being utilized in ejecting the block `from the container when the closure member I8 is released.

It is to be noted that the changes in electrical conductivity or resistance of the metallic container caused by the changes in temperature 'due to filling of the container with a solidified refrigerant, may be utilized in automatically actuating the Valve 33 admitting the refrigerant into said container, such means, for example, including a relay system which is energized whenever the readings of the flow meter' reach a predetermined point. Similarly, the closure of the switch 42 and theV supply of electrical energy to thek container for purposes of liberating the solidified refrigerant from the container may be automatically controlled. Y

As shown in Fig. 3, the resulting solidified body is in the form of a cylinder 50 provided with an axial aperture or bore indicated at I. In actual use, such body of refrigerant will vaporize or liquefy on all exposed surfaces so as to causethe finished block to evaporate to a shell, indicated by dotted line 52 in Fig. 3. As shown in Fig. 4, an indicating instrument 45 may be employed instead of the galvanometer 45 referred to in Fig. 1. The Valve 33controlling conduit 32 leading into the solidifying container may then be operated by a suitable reversible motor 53. Current is selectively supplied to proper windings of the reversible motor 53 from incoming power lines 54 by the closure of suitable contacts, by the indicating or moving armv55 of the instrument 45. When the electrical resistance of the walls of the container is high, the valve 33' will beautomatically opened and when it drops to a predetermined point, the Valve will be closed.

Those skilled in the art will observe from a contemplation of the invention described hereinabove that a novel method of making bodies of refrigerants has been disclosed wherein the formation of solidified bodies is greatly facilitated. It is to be understood that the invention is not to be limited to the specific form of apparatus disclosed nor to the utilization of all of the steps simultaneously or in sequence. The invention includes all such changes and modifications as come within the scope of the appended claims.

1. In a method of making bodies of solidified refrigerants, the steps of admitting and solidifying a liquid refrigerant in a metallic chamber, measuring the electrical resistance of the 'walls of said chamber during the admission and solidifloat-ion cf the refrigerant thereinto, and terminating theadmission of further quantities of liquid refrigerant into said chamber when the resistance of the walls of the chamber reaches a predetermined minimum.

2. In a method of making bodies of solidified carbon dioxide, the steps of introducing liquid carbon dioxide into a metallic chamber, solidifying said carbon dioxide within the chamber while continuing the introduction of further quantities of liquid carbon dioxide, measuring the electrical resistance of the walls of the chamber during said introduction and solidication of carbon dioxide, and terminating the introduction of further quantities of carbon dioxide into said chamber when the resistance of the chamber walls reaches a predetermined minimum. y

3. In a method of making bodies of solidified refrigerants, the steps of introducing a liquid refrigerant into a metallic container, solidifying said liquid refrigerant within the container while continuing the introduction of further quantities of liquid refrigerant, measuring the electrical resistance of the walls of the container during said introduction and solidification of the refrigerant in the container, terminating the introduction of further quantities of liquid refrigerant into said container when the electrical resistance of the walls of the' container reach a predetermined 5 minimum, and then passing an electric current through the walls of said metallic container in quantity suflicient to increase the temperature thereof and break the bond between the solidified refrigerant and the metallic container whereby the removal of the solidified refrigerant from the container is facilitated.

4. In an apparatus for the manufacture of solidified refrigerants, the combination of a stationary metallic container provided with a closed l5 top and an open bottom, a heat-insulated housing for said container, coils within said housing surrounding said container in which a refrigerant is allowed to expand, a removable closure for the bottom of said housing and container, means for admitting a liquid into the top of saidcontainer, and selectively operable means for raising the temperature of the Walls of said container.

5. In an apparatus for the manufacture of solidified refrigerants, the combination of a stationary metallic container provided with a closed top and an open bottom, means for admitting a liquid into the top of said container, a removable closure for the bottom of said container, electrical contact means carried by said closure, and means for supplying electrical energy to said contacts, said contacts being adapted to contact with said container whereby an electric current may be passed through the walls ofsaid container.

6. In an apparatus for the manufacture of solidified refrigerants, the combination of a stationary metallic container provided with a closed top and an open bottom, a heat-insulated housing for said container, coils within said housing surrounding said container, means for electrically insulating said housing and coils from said container, a removable closure for said housing and container, electrical contact means carried b-y said closure and adapted to contact with said container, and means for supplying electrical energy to said contacts whereby an electric current may be passed through the walls of said container.

'7. In an apparatus for the manufacture of solidiiied refrigerants, the combination of a stationary metallic container, a heat-insulated housing for said container, means for electrically insulating said coils and housing from said container, a closure for said housing and container, means for admitting a liquid into said container, and 5 means for passing an electric current through the walls of said container.

8. In an apparatus for manufacturing bodies of solidified refrigerants, the combination of a metallic container provided with a closed top and an open bottom, a longitudinally disposed core in said container, a closure member for the open bottom of said container, means for admitting a solidiiiable liquid into the top of said container, and means for passing an electric current through the walls of said container.

9. In an apparatus for the manufacture of solidified refrigerants, the combination of a metallic container provided with a closed top and anopen bottom, a longitudinally disposed core in said container, a heat-insulated housing for said container, coils within said housing surrounding said container, a closure for the open bottom of said container, means for admitting a liquid into said container, and means for passing an electric current through the Walls of said container.

10. In an apparatus for the manufacture of solidied refrigerants, the combination of a metallic container provided with a closed top and an openl bottom, a longitudinally disposed core in said container, a heat-insulated housing for said container, coils Within said h-ousing surrounding said container, a closure for the open bottom of said container, means for admitting a liquid into said container, means for measuring variations in electrical resistance of a Wall of said container, and means for passing'an electric current through the Walls of said container. v

11. In a method of making `bodies of solidified refrigerants, the steps of admitting a liquid refrigerant into a metallic container, solidifying the refrigerant in said container by expansion of another refrigerant in proximity to sai-d metallic container, measuring the electrical resistance of the container during the admission and solidification of the refrigerant in said container, and terminating the admission of further quantities of liquid refrigerant into said container when the resistance of the container reaches a predetermined minimum.

12. In a method of making bodies of solidied carbon dioxide, the steps of introducing liquid carbon dioxide into a metallic container, solidifying the carbon dioxide Within the container by expanding a refrigerant in proximity to said container while continuing the introduction of further liquid carbon dioxide, and controlling the introduction of liquid carbon dioxi-de into said container by temperature variations of the walls of said container.

13. In a. method of making'bodies of solidified carbon dioxide, the steps of introducing liquid carbon dioxide into a metallic chamber, solidifying said carbon dioxide within the chamber by expandingl a vrefrigerant in proximity to said chamber while' continuing the introduction of further quantities of. liquid carbon dioxide, measuring the electrical resistance of the Walls of said chamber during said introduction and solidiiicav tion of carbon dioxide, and terminating the introduction of further quantities of carbon dioxide into said chamber when the resistance of the chamber' Walls vreaches a predetermined minimum;

14. lin a method of making bodies of solidied carbon dioxide, the steps of admitting a liquefied carbon dioxide into a metallic container, and controlling the introduction of liquid carbon -dioxide into the container in accordance with indicated variations in temperature of the metallic container.

15. In a method of making bodies of solidiiied carbon dioxide, the stepsof admitting liqueed carbon dioxide in a metallic container, controlling the intro-duction of liquid carbon dioxide into the container in accordance with indicated variations in temperature of the metallic container, and ejecting solidied carbon dioxide from the container by varying the temperature of the metallic container.

WALTER GORDON CLARK. 

